Tobacco flavorants



United States Patent 3,095,832 TUBACCO FLAVORANTS John D. Hind and FrankH. Crayton, Richmond, Va, assignors to Philip Morris Incorporated, NewYork,

.Y. a co oration of Virginia NO him-3 Filed Aug. 4, 1961, Ser. No.129,240 17 Claims. (Cl. 131-17) This invention relates to flavorantssuitable for incorporation in tobacco and tobacco products. Moreparticularly it relates to volatile flavorants which contribute topackage aroma of tobacco products and/or to the flavor of the tobaccoproduct upon its being smoked.

It has long been common to alter, enhance and improve the flavor andaroma of tobacco productsby 1ncorporating therein, by various methods, avariety of flavoring and other ingredients. Sugar, lrco-rrces, and othercondiments have frequently been used for this purpose, and it has alsobeen suggested to incorporate more uncommon flavorings on the leaf oreven to in ect them within the living plant. The present invention,however, relates particularly to incorporation ofyolatrle derivatives ofsubstances native to the tobacco itself to provide flavorful and usefulenhancement of smoking products. The flavorants of this invention may beincorporated in the tobacco or placed on the filter or may be otherwiseassociated with the package.

A particularly sought after object in the tobacco preparation art is toenhance the sweetness of tobacco poducts. This has been attempted byaddition to the tobacco of raw sugars, either as such or in the form ofmaterials rich in sugars, e.g., molasses. Such materials, while alteringthe flavor of the tobacco product, are unsatisfactory in that theirburning characteristics are markedly different from those of tobacco.Particularly where moderate or higher levels of sweetness are desired,either for their own flavor values or to complement other additives orflavors incorporated in the tobacco, it is found that loading thetobacco with substantial quantities of such sugars interferes with itscombustion to an unacceptable extent.

We have found, in one aspect of our invention, that sweetening agentsparticularly well adapted for incorporation in tobacco products may beprepared from substances native to tobacco leaf. We have further foundthat such derivatives, Whether prepared from tobacco itself orsynthetically, contribute the desired sweetness, yet do not interferewith combustion of the tobacco product.

We have also found that certain other derivatives of substancesnaturally occurring in tobacco, whether prepared from tobacco sources orsynthetically, contribute subtle and highly pleasing characteristicsother than sweetness to the smoke.

It is accordingly an advantage of this invention that sweetening agentsand other flavorants are provided which do not interfere with thecombustion of the tobacco product even when such agents are present inrelatively high quantity. Thus, the flavorants of this invention are allvolatile, by which is meant that they vaporize at a temperature belowthe pyrolysis temperature of tobacco and distill oif ahead of the coal,little if any of such materials being consumed by combustion. A furtheradvantage of the present invention is that novel and useful subtleflavorants are provided for incorporation in tobacco in whatevercombination or ratio may be desired.

In accordance with one mode of the present invention, desirable anduseful flavorants for incorporation in tobacco products, whichflavorants are characterized by volatility and by a sweet flavor, areprepared by alcoholysis of saccharides. Other desirable and usefulproducts 3,095,882 Patented July 2., 1963 "ice which contributedesirable and characteristic odors to the tobacco product before andduring smoking are de rived by alcoholysis of organic acids or mixturesthereof, and particularly by alcoholysis of organic acids which arenative to tobacco, to provide products which volatilize below thepyrolysis temperature of tobacco.

The flavorful products may be incorporated in tobacco individually, withor without other commonly used flavors, humectants and other familiaradditives, or they may be selectively combined and blended inappropriate proportion to provide dilfering subtle and pleasingcharacteristics to pack aroma and smoke.

The alcohols which may suitably be used in the prac tice of the presentinvention include the lower alkyl alcohols, i.e., those having from 1-6carbon atoms. Other suitable alcohols may be determined by simple trial,the criterion being that the product be volatile below the pyrolysistemperature of tobacco and that the product have desirablecharacteristics of flavor and/or aroma.

A wide variety of saccharides may be used in the practice of thisinvention and include, without limitation, the monosaccharides,idisaccharides, trisaco'harides, tetrasaccharides and polysaccharides,so long as their reaction products with alcohol are volatile andpleasing, as above discussed. The monosaocharides, disaccharides andpolysaccharides are generally preferred, and especially the hexoses,pent-oses, dihexoses, such as sucrose, and polyhexoses, such asdextrins, starches, and fructosans.

Likewise, the organic acids which may be rused to advantage are thosewhich in reaction with the alcohol or mixture of alcohols employed 'willyield volatile prodnets of desirable characteristics. The preferredorganic acids are those naturally occurring in tobacco, including thealiphatic polycarboxylic acids, particularly the alipliatic diandtri-carboxylic and hydroxycarboxylic acids, and include, withoutlimitation, malonic acid, malic acid, succinic acid, tartaric acid andcitric acid. Desirable flavorants include lower alkyl malates, loweralkyl mal onates, lower alkyl succinates, lower alkyl tartrates andlower alkyl citrates.

Desirable flavorants contributing a sweet flavor or aroma include,without limitation, (lower alkyl) oxymethyl furfurals and lower alkyllevnlinates.

The amount of flavorant incorporated in tobacco in accordance with thisinvention is largely a matter of choice. As a minimum, an effectiveamount should be incorporated to contribute a discrete aroma and/ orflavor to the product or to its smoke. Any larger amounts depend uponthe character and extent of enhancement de sired, and we have found thattheir effect is more pleasing when subtle. We have found further, thatthe flavorants of this invention tend to complement each other andcommonly used flavor additives and that by' varying proportions andamounts within the skill of the formulator, unusual pleasing anddesirable effects can be achieved. The flavorants may be incorporated intobacco by spraying, dipping, or other conventional means.

Appropriate process and equipment to prepare the flavorants of theinvention will be apparent to those skilled in the art and form no partof the present invention. Suitable exemplary processes and equipmentwill be apparent from the following examples, which are intended to beillustrative and are not to be taken in a limiting sense. Except asotherwise indicated, all parts are by weight.

Example 1 3500 ml. of absolute methanol and 138.5 m1. of concentratedaqueous hydrochloric acid are placed in a 5- liter trident flask andheated to 40 C. 400 g. of sucrose fruity odor. The second fraction issubstantially methoxymethyl furfural and has an odor suggestive ofmaraschino cherries. The over-all yield is 25 .3

Example 2 15 liters of anhydrous ethanol, 457 ml. of concentrated HCland 2000 g. of sucrose are placed in a S-gallon carboy, which is shakenoccasionally and then left to stand overnight. In the morning the carboyis placed in a constant temperature bath for three hours at 50 C. withcontinuous stirring to insure that all sugar is in solution. The bath isthen brough to 75 C. and the carboy contents are held at thattemperature for 24 hours. The mixture is thereafter cooled andneutralized with 391 ml. of 41% NaOH to pH 6.5. V

The reaction mass is vacuum distilled under continuous water aspiratorvacuum to remove excess alcohol. The syrupy residue is ether-extractedin two batches in a continuous liquid-liquid extractor with ethyl ether,and the ether is removed by heating gently at atmospheric pressure. Thetwo batches of extracted material are vacuum distilled at 1-2 mm. ofmercury to produce four fractions for batch #1 and three fractions forbatch #2. Fractions I and IV of batch #1 and Fractions 1 and iii ofbatch #2 are identified as ethyl levulinate (B.P. 51-64 C. at 2. mm. Hg)and etlioxymethyl furiural, respectively, by gas chromotography. Theintermediate fractions are mixtures of the two. The yield of ethyllevulinate is 6.25 that of ethoxymethylfurfural is 9.0%; total yield is23.5%

Example 3 12 ml. of concentrated aqueous hydrochloric acid and 500 ml.of n-propyl alcohol are placed in a one-liter trident flask equippedwith an air-driven stirrer and a fractionating column. The flaskcontents are brought to 60 C. with a Glas-col mantle and 50 g. sucroseis sifted into the flask with continuous stirring. The sugar dissolvesin about 14 hours. The reaction isa'ccompanied by color changes fromclear and colorless to yellow, to orange, to red, and finally to black.

The solution is then distilled at an overhead temperature range of 87 C.to 97 C., yielding about200 ml. of distillate, principally the azeotropeof water and npropanol.

The contents remaining in the reaction flask are refluxed withcontinuous stirring for a total of 14 hours at 95 C. and then distilleduntil a head temperature of 95 C. is reached, at which point thedistillate is dry (in the sense that it will not dissolve a crystal ofsodium chloride). Approximately 250 m1. of product distillate arerecovered.

The odor of the product, a black-walnut type note, indicates thatesteriiicatio'n has taken place. The distillation range of the productcorresponds to the boiling points of n-propyl levulinate andn-propoxymethyl furfural,

showing these expected compounds to have been formed.

500 ml. of 99% isopropanol is placed in a one-liter trident flaskequipped with, an air-driven stirrer and a fractionating column. 12 ml.of concentrated aqueous hydrochloric acid is added and the temperatureraised to 60 C. 50 g. of sucrose is shifted into the flask and themixture is stirred constantly while the sugar is going into solution, aperiod of about l%.2 hours. The contents of the flask are then distilledto remove the water. The flask contents are refluxed at C.-82 C. forapproximately 14 hours with constant stirring and then distilled at ahead temperature of 82 C.

Approximately 220 ml. of product is removed from the reaction flask. Theodor is similar to, but slightly dillerent from, that of the n-propyllevulinate and n-propoxymethyl turfural prepared in Example 3. The odoris reminiscent of nuts, but does not have the distinct blackwalnut typenote which characterizes the n-propoxymethyl furtural.

Under vacuum distillation, a product yield of 19.95% is obtained. Thematerial has a sweet, ethereal odor.

Example 5 V 50 g. of sucrose, 500 ml. of iso-butyl alcohol and 12 ml. ofconcentrated aqueous hydrochloric acid are reacted according to theprocedure of Example 3. A 17.45% yield is obtained.

The products are identified by their distillation points as iso-butyllevulinate and iso-butoxymethyl furfural. Their odor is stronger andmore distinct than that of the products prepared frornlower members ofthe alkyl alcohol series.

' Example 6 50 g. of sucrose and 500 ml. of n-butyl alcohol are placedin a one-liter trident flask equipped with an airdriven stirrer and afractionating column. The tempera ture is raised gradually to 60 C. witha Glas-col mantle. The mixture is stirred for 3 hours and then allowedto stand over the Weekend. The temperature is again brought to 60 C. for1 hour with stirring, additional water being added to bring undissolvedsugar into solution. 12 ml. of concentrated hydrochloric acid is thenadded.

The procedures of Example 3 are followed to remove the product, theyield being 16.1%. The products are vacuum distilled and identified bytheir distillation points as n-butyl levulinate and n-butoxymethylfurfural. The n-butyl levulinate has a woody, ethereal odor that israther sharp.- The n-butyoxymethyl furfural has a sweet but woody odor.

Example 7 10 g. of sucrose, m1. of n-hexanol and 0.5 ml. of concentratedhydrochloric acid are placed in a pressure bottle. The bottle isstoppered and partially immersed in a constant-temperature water bath.The reactants are maintained at 77 C. for 72 hoursand at 84 C. for 24hours, whereupon the bath is allowed to cool with the bottle stillimmersed.

An aliquot of the reaction product, which is dark in color, isneutralized with sodium hydroxide to pH 7, evaporated to semi-dryness,and submitted to a panel for odor evaluation. The following subtle notesare detected: sweet and spicy; nutty (a green Walnut odor); fruity. Allof these notes differ from those detectable in sucrose or in hexanol,and it is evident that they are present as a direct consequence of thereaction.

Example 8 To a pressure bottle are added 5 g. sucrose, 10 g. potassiumacid sulfate (KHSO and 100 ml. of neutral ethyl alcohol. The bottle isloosely stoppered and immersed in a 70 water bath for 2 hours, beingshaken occasionally during this time.

The reaction bottle is then placed in a 60 C. forced draft oven andheated for 16 hours. On removal from the oven, the contents are lightyellow in color and have a very pleasant odor, quite difierent fromalcohol, which indicates the predicted reaction has taken place. A testpanel identifies these odor notesrin the sample: apple, fruit aroma andcoconut.

Example 9 Three Erlenmeyer flasks are prepared, each containing 300 g.of dried bright tobacco stems (ca. 8% reducing sugar) covered with 700ml. of anhydrous ethanol. The alcohol in flask #1 is acidified with 58ml. of HCl, that in flask #2 with a mixture of 29 ml. HCl and ml. ofconcentrated H 80 and the third with 20 ml. concentrated H 80 All threeflasks contain the same stoichiometric acid equivalents.

The flasks are placed in a water bath at 75 C. for hours and theircontents are then neutralized. Samples are taken and diluted. Flavor andaroma are found to be most preferred in the H SO -catalyzed product,followed by the mixed acid product, and the HCl-catalyzed product israted third.

Example 10 100 g. starch (dry Wt.) and 500 ml. of ethanol containing 7%HCl are added to a one-liter flask and refluxed 5 hours. Vacuumdistillation of the reaction product gives 11 g. of ethyl levulinate and3.9 g. of ethoxymethyl furfural.

Example 11 To a flask are added 5 g. of molasses, 200 rnl. anhydrousethanol and 7.3 ml. concentrated H 80 The reactants are heated for 18hours at 75 C. Flavor notes indicate that reaction of the characterheretofore described has taken place.

Example 12 To a flask is added 5 g. fructose, 150 ml. SD #30 alcohol(ethanol containing about 10% methanol and 7.3 ml. of concentrated H 50The flask contents are reacted for 96 hours, at elevated temperaturesbetween 50 C. and 70 C. A sample is diluted with an equal volume ofWater and neutralized with NaOH to pH 6.5. A sweet odor, very similar tothe odor produced by the same reaction With bright stems, is found andcan be detected even when the reaction mixture is diluted to 1:2000.

Example 13 To a one-liter flask are added 40 g. of DL malic acid, 1000ml. of anhydrous ethanol and 70 ml. of acidic alcohol (16.2 g. HCl/ 100ml. of ethanol). The flask is connected to upward air and downward watercondensers and the contents are heated for 6 hours and 43 minutes,during which time 474 ml. of alcohol are removed. The flask contents arethen neutralized to pH 7.0 with 41% NaOH. A 40.04 g. (73%) yield of thedistillate of the expected boiling point is obtained when the residue isvacuum distilled at 2.5 of mercury. The product is identified as diethylmalate by gas chromatography.

Example 14 Esters of other acids may be prepared by the procedure ofExample 13. Illustratively, by employing n-butanol and succinic acidthere is obtained di-n-butyl succinate, which has an odor note ofbutyric acid, sweet, and with relatively low overall intensity.

Example 15 A five-gallon Pyrex carboy is loaded with 12.5 pounds oftobacco (dried bright stems) and covered with 12 liters of ethanol mixedwith 1000 ml. of concentrated hydrochloric acid. The carboy and contentsare maintained at a constant temperature of 68 C. for 17 /2 hours. Thetemperature is then raised to 75 C. for 4% hours. The liquor from thecarboy is recovered and diluted to 12 liters with fresh ethanol and acidin the same proportions and poured into a second carboy containing 12.5pounds of fresh dried bright stems. The procedure is as before, withrecovery of liquor and its reaction with a third carboy of stems in thesame manner.

The resultant product liquor obtained from the third carboy of thecountercurrent series is neutralized to pH 6.3

with sodium hydroxide and placed under water aspirator vacuum to removeexcess alcohol. The residue is transferred to a continuous extractor andrun approximately 18 hours with ether. The ether is removed by boilingat atmospheric pressure and any remaining traces of ether are removed byplacing the residue in a water aspirator vacuum. The product is placedin a Claisen flask and vacuum distilled at 2-3 mm. of mercury.

To an alcoholic solution of a portion of the light yellow distillate isadded a reagent solution of 2,4-idinitrophenyl hydrazine and fourderivatives are obtained. Two of these melt at the correct range forethyl levulinate and ethoxymethyl furfural. Gas chromatographicseparation of the products in the distillate shows it to consistprincipally of diethyl malate, diethyl succinate, ethyl levulinate, andethoxymethyl furfural. These components are further identified by massspectrometry and by infrared spectrophotometry.

The separated components may be blended with tobacco singly or indesired admixture.

Example 16 The pleasing, distinctive and subtle attributes of exemplaryflavorants in accordance with this invention when embodied in smokingproducts are illustrated by the present example. Three lots of regularcigarette filler, weighing ten grams each, are sprayed With a mixture ofethoxymethyl furfural, ethyl levulinate, diethyl malate, diethylsuccinate, and diethyl citrate. Half the mixture comprises ethoxymethylfurfural and ethyl levulinate, prepared as in Example 2, and the otherhalf comprises substantially equal parts of the three specifiedcompounds, all parts being by Weight. The amount of the mixture offlavorants applied to the filler is about 0.3% by weight of the filler.Amounts within the range of 0.1% to 1% have been found satisfactory,with 0.2% to 04% being preferred.

The treated filler is dried and made into cigarettes for evaluation ofpleasing odor and taste. The cigarettes so prepared and untreatedcontrol cigarettes are submitted to a panel of three judges, who use a0-10 intensity scale in aid of evaluation.

The panel finds that the cigarettes containing the flavorful additivesof this invention are characterized by a fruity odor in unlit draw tasteand in smoke taste and are readily distinguishable from the controls.The flavorants are found to enhance significantly the taste and odor ofthe tobacco filler. Data from the test is given below.

1. A tobacco product containing a flavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said flavorantbeing the reaction product of an alcohol and a member of the groupconsisting of saccharides and organic acids native to tobacco.

2. A product containing a flavorant characterized in being volatilebelow the pyrolysis temperature of tobacco, said flavorant being thereaction product of a lower alkyl alcohol and a saccharide.

3. A tobacco product containing a flavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said flavorantbeing the reaction product of a lower alkyl alcohol and a member of thegroup consisting of hexoses, pentoses, dihexoses, dextrins, starches andfructosans.

4. A tobacco product containing a fiavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said fiavorantbeing a (lower alkyl) oxyrnethyl furfural.

5. A tobacco product containing a flav-orant characterized in beingvolatile below the pyrolysis temperature of tobacco, said fiavorantbeing a lower alkyl levulinate.

6. A tobacco product containing ethoxyrnethyl furfural.

7. A tobacco product containing ethyl levulinate.

8. A tobacco product containing a ilavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said flavorantbeing the reaction product of a lower alkyl alcohol and an organic acidselected from the group consisting of aliphatic diand tri-c-arboxylicand hydroxycarboxylic acids.

9. A tobacco product containing a fiavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said flavorantbeing a lower alkyl malate.

10. A tobacco product containing a fiavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said fiavorantbeing a lower alkyl succinate.

11. A tobacco product containing a flavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said fiavorantbeing a lower alkyl citrate.

12. A tobacco product containing a flavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said flavorantbeing a lower alkyl malonate.

13. 'A tobacco product containing a flavorant characterized in beingvolatile below the pyrolysis temperature of tobacco, said flavorantbeing a lower alkyl tartratc.

14. A method of enhancing the flavor and aroma of a tobacco productwhich comprises incorporating in said tobacco product an efiectiveamount of at least one flavorant which is the reaction product of analcohol with a member of the group consisting of saccharides andaliphatic diand tri-carboxylic and hydroxycarboxylic acids, saidfiavorant being characterized in being volatile below the pyrolysistemperature oftob'acco.

15. A method of enhancing the flavor and aroma of a tobacco productwhich comprises incorporating in said tobacco product an effectiveamount of a flavorant which is the reaction product of a lower alkylalcohol and a member of the group consisting ot aliphatic diandtricarboxylic and hydroxycarboxylic acids, said fiavorant beingcharacterized in being volatile below the pyrolysis temperature oftobacco.

l6. Amethod of providing a sweet flavor in the smoke of a tobaccoproduct which comprises incorporating in said tobacco productan'effective amount of the reaction product of an alcohol and asaccharide, said reaction product being characterized in being volatilebelow the pyrolysis temperature of tobacco.

17. A method of providing a sweet flavor in the smoke of a tobaccoproduct which comprises incorporating in said tobacco product aneffective amount of the reaction product of at least one lower alkylalcohol and at least one member of the group consisting of hexoses,pentoses, dihexoses, dextrins, starches and fructosans, said reactionproduct being characterized in being volatile below the pyrolysistemperature of tobacco.

References Cited in the file of this patent UNITED STATES PATENTS2,766,145 Jones Oct. 9, 1956 2,766,146 Ashburn Oct. 9, 1956 2,766,150Teague Oct. 9, 1956

1. A TOBACCO PRODUCT CONTAINING A FLAVORANT CHARACTERIZED IN BEINGVOLATILE BELOW THE PYROLYSIS TEMPERWTURE OF TOBACCO, SAID FLAVORANTBEING THE REACTION PRODUCT OF AN ALCOHOL AND MEMBER OF THE GROUPCONSISTING OF SACCHARIDES AND ORGANIC ACIDS NATIVE TO TOBACCO.